In integrated circuit manufacturing processes, devices such as transistors are formed at the surfaces of semiconductor chips. The devices are isolated from each other by isolation regions. Shallow Trench Isolation (STI) regions are commonly used as the isolation regions to isolate active regions of the semiconductor substrate. Typically, STI regions are formed of a dielectric material or dielectric materials filled into trenches in semiconductor substrates.
The integrated circuits that adopt the STI regions still suffer from drawbacks, which include leakage currents at the junctions of p-type and n-type regions. For high-voltage devices, the conventional integrated circuits further suffer from low breakdown voltages and latch ups.